Workpiece table arrangement

Abstract

A workpiece table arrangement for a milling and drilling machine comprising a rigid machine tool frame comprising an upper cross girth, a machining unit movable on the front side of the cross girth along at least two coordinate axes by means of a motor and including a rotationally driven work spindle including exchangeable tools. The workpiece table is disposed in front of the machine tool frame and horizontally movable along at least one coordinate axis by means of a motor and comprises a tabletop for clamping at least one workpiece. The machine tool frame comprises two rigid side walls rigidly connected to each other by the upper crossbar and a front end.

1. A workpiece table arrangement for a milling and drilling machine comprising a rigid machine tool frame comprising two generally parallel side walls having inner sides and front end portions, and an upper crossbar attached to said side walls, a machining unit movable on said upper crossbar along at least two coordinate axes and including a rotationally driven work spindle configured to engage exchangeable tools, a front end comprising the front of said machine tool frame and having horizontal guide rails mounted on said front end, the workpiece table arrangement comprising:
 a bridge comprising a central bar and being pivotable about a horizontal axis; 
 a plane table top coupled to said central bar and comprising clamping means for clamping workpieces thereto; 
 the bridge further comprising a bearing leg connected to each end of said central bar of said bridge, said bearing legs being supported in a respective slide so as to be synchronously rotatable; and 
 said two slides each comprising a portion of a drive unit for moving the respective slide and a guide shoe, wherein the respective portions of the drive units are primary parts of electrical linear drive motors, the primary parts being mounted on a vertical face of a respective slide. 
 
   
   
     2. The workpiece table arrangement according to  claim 1 , and further comprising electrically synchronized torque motors disposed in said slides, said torque motors acting as swivel drives for said bridge. 
   
   
     3. The workpiece table arrangement according to  claim 2 , wherein said torque motors in said slides are internal rotor motors having cooled external stators. 
   
   
     4. The workpiece table arrangement according to  claim 1 , and further comprising fixing devices disposed in said slides for arresting said bridge in selected positions. 
   
   
     5. The workpiece table arrangement according to  claim 1 , wherein said bearing legs of said bridge are supported in said slides via bearings. 
   
   
     6. The workpiece table arrangement according to  claim 1 , wherein said plane table top is supported in said central bar of said pivotable bridge so as to be rotatable by means of a torque motor. 
   
   
     7. The workpiece table arrangement according to  claim 6 , wherein said torque motor is an internal rotor motor having a cooled external stator. 
   
   
     8. The workpiece table arrangement according to  claim 6 , wherein said torque motor is located in said central bar of said pivotable bridge. 
   
   
     9. The workpiece table arrangement according to  claim 1 , wherein secondary parts of the electrical linear drive motors are attached to said side walls of said machine tool frame. 
   
   
     10. The workpiece table arrangement according to  claim 9 , wherein said linear motors of said two slides are electrically synchronized. 
   
   
     11. The workpiece table arrangement according to  claim 9 , and wherein the slides include end side extensions, said vertical faces on which said primary parts are mounted being located on said end side extensions. 
   
   
     12. The workpiece table arrangement according to  claim 1 , wherein a rotational axis of bearings of said bearing legs of said pivotable bridge in said slides extends approximately on the level of a surface of said table top. 
   
   
     13. The workpiece table arrangement according to  claim 1 , and further comprising arcuate transitions between said central bar and said bearing legs, wherein said central bar of said pivotable bridge, as well as said two bearing legs and said arcuate transitions between said central bar and said bearing legs, are formed with double walls.